This series “Digital security” is from my notes prepared for certifications.
If the key of a Symmetric-key algorithm is compromised, a malicious actor can sniff on all the encrypted traffic.
An algorithm that doesn’t require the same key to be shared by both parties to encrypt and decrypt data is an Asymmetric-key algorithm.
A key-pair is generated by one party A. This key-pair has two keys that are mathematically linked together. A retains a key (which is then called the private key).
The other key is called a public key and it is shared with everyone, including the other party B with whom secure communication is desired.
B encrypts a message using the public key and sends it back to A.
Even though everyone else other than A and B have the public key, they can’t decrypt the message.
The message can only be decrypted using the private key which is only with A.
Step 1: Both parties generate their private and public key-pair.
Step 2: Both parties exchange each other’s public keys.
Step 3: A encrypts a message using B’s public key and sends that to B.
Step 4: B decrypts the message using their private key to get A’s original message.
Similarly, B can encrypt a message using A’s public key which is then decrypted by A using their private key.
Once a party encrypts a message using the public key, only the corresponding private key can decrypt the message.
If the private key is compromised, all messages encrypted by the paired public key can be decrypted using it.
If a public key is compromised, false encrypted messages can be sent to the owner of the paired private key.
If one keys in a key-pair encrypts a message, only the other key in the key-pair can decrypt it.
The same key that encrypts a message, can’t decrypt it.
RSA(Rivest, Shamir, Adleman), DSA(Digital Signature Algorithm) and ECDSA(Elliptic Curve DSA) are most common asymmetric cryptographic algorithms.
kskspeaking 